The latest installment of the rather twisted ero-anime Euphoria has resumed its dastardly shock-inducing perversion, this time allowing yet more girls to experience the show’s vast selection of sexual depravity – though to much lesser extremes in comparison to previous episodes.

Wait.. i thought the same.. the last time i watched it, that Psycho Girl was jerking off that Dude while he was naked and blindfolded, while showing off the other girls who got either decapitated, Drowned or whatever..

There is a glimpse of the future after the credits in episode 2 showing the stuff you described.
It could have been an end to the series (and maybe it is the ending) the episodes after that go back to 'present time'.
It kinda spoils the 'story' a bit.

If you played the visual novel of Euphoria, you'd know the story is pretty damn sad.

*spoiler*
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The main character, Keisuke, is forced to re-live this game over and over, like the movie Source Code. Everytime he reaches the exit, the game would restart. The whole thing is a virtual reality, created by using Nemu's vegetable-state mind. Nemu is born with the power to create "dream worlds", and the condition is to have her experience endless sadness so that she would never wake up. The flash back Keisuke keep having with his childhood friend Kanae is all fake. Kanae, a scientist, injected the fake memory to make Keisuke hate Nemu, which is his real childhood friend. Everything Kanae seems to be in the game, is the real Nemu in reality, and everything Nemu stands for, is Kanae in reality; Their role basically exchanged. When Keisuke finally realize everything is fake and a forced-hibernation, he wakes up to find himself inside a lab. He searched around for Nemu, just to find her already beyond help. The lab corporation knew Nemu wouldn't last forever so they cloned her, to continue "the kingdom project". Keisuke found the child Nemu-clone, and escaped with her.

If you think about it logically, it's pretty understandable. Here are some ways in which scat is arousing:

- Sex is arousing because of its deviant nature. You have words like "naughty", "dirty" being used. What is more deviant than shit, which is usually confined to the toilet, taken out of that space?

- Sex is arousing because it is intimate. Therefore, just like other body fluids like pussy juice or piss, it's something that the girl you liked produced from her body. It's not any shit, it's her shit.

- Sex is arousing because of the feeling of being in power. By having a girl shit herself, you are forcing her to show you something that is intimate and private, embarrassing and infantalizing herself, making you feel in control.

- Playing with shit and smearing shit all over her combines all of the above. It's dirty, intimate and humiliates her.